Image: San Diego Sustainable Living Inst.
Image: San Diego Sustainable Living Inst.

When it comes to water conservation the solutions are not black and white, they’re grey. You will find it (correctly) spelled greywater and graywater but whether you spell it with an ‘e’ or an ‘a’ it is one of the smartest strategies for maximizing your water economy.

You see, we in the state of California spend around 20% of our overall energy making water potable and moving it around. There’s even a word for that, ‘watergy’ refers to the energy we spend on the wet stuff. So with graywater you can help reduce watergy, save money and the water itself by keeping laundry water on your site.

Technically, greywater is all used house water sources (shower, bathtub, bathroom sinks) except the ‘blackwater’ from toilets and kitchen sinks. A ‘laundry to landscape’  system is often the easiest to install. This type of system cuts the pipe going to the sewer or septic and diverts it via tubing into multiple ‘mulch basins’ where it can safely infiltrate into the ground to hydrate the root zone of garden and landscape plants.

The State of California has guidelines that make it clear how to install a safe greywater system. As long as twelve basic guidelines are followed no permit is needed for Laundry to Landscape Greywater Irrigation Systems. A permit is needed when any change is made to the household drainage plumbing.

Although no deaths have ever been reported from the use of graywater, it is wise to prevent possible contamination from above ground pooling. With these guidelines greywater never sees the light of day or the inside of a storage tank for that matter. Storing graywater is a bad idea. It becomes a science experiment within 24 hours turning it from grey to blackwater.

Five Steps Explained

1.  The laundry out-flow water is diverted with a three way valve installed right next to the washing machine. This gives you the option of diverting the water back to the sewer or septic if needed for any reason.  For example: if you are going to use bleach in the laundry or the ground is saturated from rain you would divert the graywater away from the landscape with this valve.

Image: Ken Foster

2.  Next: it is important to install an auto vent. This ‘air admittance valve’ is to let air into the pipes to break the siphon of the laundry machine pump. The auto vent should always be placed AT LEAST 6 inches above the fill line of the washing machine.

Greywater clearified4
Image: Ken Foster

3.  The graywater flows out to the landscape through one inch poly tubing were it is dispersed at multiple ‘mulch basins’. The number of mulch basins depends on what size the wash load is and how many loads are done per week. Between 5 and 10 mulch basins is typical. A mulch basin is simply a 2 foot x 2 foot hole dug in the soil and filled with wood chips. Each mulch basin has a manual shut off valve so you can make the call where the water is dispersed.

Greywater clearified7
Image: Ken Foster

4.  To make the Graywater friendly to plant and tree roots it is important to only use laundry soaps that have no chlorine bleach, dyes or chemical scents that can be harmful to plants. Here are a few examples of ‘Greywater’ friendly laundry soaps:

Oasis Laundry Detergent (liquid), ECOS liquid detergent, Vaska, and Dr. Bronners liquid soap. Vaska also makes a commercial laundry detergent that is compatible with commercial washing machines.

greywatered plants
Image: Ken Foster

5.  Finally it is advised that graywater not be used directly on leaf vegetables, root crops or grass for that matter. A mulch basin near the root zone of a fruit tree is a good example of the best use of greywater. As you reduce water consumption, using a graywater system allows you to water even as you mind landscape water restrictions.

I hope this gives you a good idea how the laundry to landscape greywater system actually works, and I encourage you to try it. Should you have any questions please feel free to leave a comment or give us a call if you are in Monterey Bay area, or the San Jose area.

Ken Foster, is a landscape contractor and the owner of Terra Nova Ecological Landscaping. Ken is a certified permaculture designer and gives talks on topics related to sustainable landscaping including ‘Fossil Free Landscaping’, sustainable design, hardscape and softscape installation and maintenance. He is a native of Santa Cruz, California.

Special offer to our readers: Call Terra Nova Ecological landscaping to schedule a free estimate for a ‘Laundry to Landscape’ graywater system and receive $50.00 dollars off through March, 2014.

5 thoughts on “Laundry to Landscape Greywater System Explained in Five Steps”
  1. Thanks, I loved reading about this, and appreciate the good information. In the next couple years I believe we will see many home conversions to graywater. It will seem increasingly important to use water efficiently. It will become mainstream. People who would never have considered it in the past are starting to view it as a worthy home improvement project — and normal, not “out there”.

  2. This is a very straight-forward description of how a graywater system works. It is easy to understand, and to implement. Thanks, Ken, for defining a graywater system so clearly!

  3. Thank you for explaining the basics of the greywater system so succinctly—I’m not handy, so I appreciate being taken through it step by step. I wish I had known about this years ago! Using greywater seems like a smart, practical, and painless way to save water—especially for us Californians who live on “borrowed” water. I suggest posting this article on so that people who are planning a home remodel can learn about this important and elegant way to conserve our most precious resource.

  4. Great article thanks Ken. Water conversation is at the top of the list now here in California. These are all good ideas how we can conserve. I have a rain barrel for the first time I will implement Ken’s ideas as well.

  5. This was a very clear and informative article.

    I am also very interested in doing “shower to landscape,” and would love to see a similar article – I know one has to get a permit.

    I also want to comment: The water we save by installing laundry to landscape systems, front loading washing machines, drip irrigation, etc. is nothing compared to the water we waste when we eat meat. The quantity of water that is used to produce one pound of meat is astonishing. Even when it is organic, if it is not exclusively grass-fed, there is the issue of how much grain (which has to be planted, weeded, irrigated, harvested, etc.) goes to produce one pound of meat – and then there are all the polluting waste products and the possibility of fecal contamination. The biggest way we can save water is to eat a plant-based diet!

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